Abstract:
The etching conditions of an indigenously prepared thin film of pentaerythritol tetrakis(allyl carbonate) (PETAC) were standardised for the use as a nuclear track detector. The optimum etching times in 6 N NaOH at 70 degrees C for the appearance of fission and alpha tracks recorded in this detector from a 252Cf solid source were found to be 30 min and 1.50 h, respectively. The experimentally determined values for the bulk and track-etch rates for this detector in 6 N NaOH at 70 degrees C were found to be 1.7 plus or minus 0.1 and 88.4 plus or minus 10.7 mu m/h, respectively. From these results, the important track etching properties such as the critical angle of etching, the sensitivity and the fission track registration efficiency were calculated and compared with the commercially available detectors. The activation energy value for bulk etching calculated by applying Arrhenius equation to the bulk etch rates of the detector determined at different etching temperatures was found to be 0.86 plus or minus 0.02 eV. This compares very well with the value of about 1.0 eV reported for most commonly used track detectors. The effects of gamma irradiation on this new detector in the dose range of 200–1000 kGy have also been studied using bulk etch rate technique. The activation energy values for bulk etching calculated from bulk etch rates measurements at different temperatures were found to decrease with the increase in gamma dose indicating scission of the detector due to gamma irradiation. The optical band gap of this detector was also determined using UV–visible spectrometry and the value was found to be 4.37 plus or minus 0.05 eV.
